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Discuss iPhone Antenna Design Flawed at the General - Hackint0sh.org; There is a story up on slashdot ( iPhone Signal Strength Problems In the UK ...
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    Exclamation iPhone Antenna Design Flawed

    There is a story up on slashdot (iPhone Signal Strength Problems In the UK) reporting persistent problems with signal strength on O2. While there is no much information in it, there was on very interesting comment on it which I am quoting below

    While metal is shiny and slick, when it is too close to an antenna, the bandwidth decreases. So the antenna designer has a choice of which frequencies to focus their design effort. Since their initial target market was the USA, they probably targeted GSM850 (AT&T's GSM network). From the antenna photos, the GSM 1800/1900 part of the antenna is the part closest to the battery/metal covers, which further degrades performance in this band. One of the earlier replies said their iPhone worked fine in the country-side of the UK. This is most likely due to the GSM850/900 part of the antenna being furthest away from the battery/metal covers.

    iPhone disassembled:
    http://www.ifixit.com/Guide/iPhone/C...ications-Board [ifixit.com]

    One can see a small little cable going from the RF Module to the antenna. In almost 99% of the GSM phones on the market today, the antenna is right next to the RF Module. This is to minimize the RF losses between the RFIC and the antenna. By using a cable, significant losses are introduced into the system by both the cable and the miss-match at both ends of the cable. The antenna is also at the bottom of the phone and is more likely to be covered by the user's hand (further decreasing sensitivity); though there are quite a few phone on the market with antennas at the bottom--it is how they get around the SAR limits which are specified as the peak radiation a user receives next to their ear (the mouth area is not measured in the FCC/EU tests.

    So, while from an anecdotal perspective, it appears the iPhone has random sensitivity issues; from an antenna engineer's perspective however, it is no surprise why the iPhone has lower performance than most phones (but would still have similar performance to other phones with poor antenna designs--of which there are several for different reasons than cable losses).



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    I find it strange that people in the uk are having issues. We haven't heard many reports of t-mobile us users having issues, have we (t-mobile us uses 1900 only)? At least, I haven't seen it, and I'm a t-mobile user myself as well. I haven't had signal issues anywhere that other phones haven't had issues.

 

 

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